1. Field of the Invention
The present invention relates to an image data processing technique to process input image data of images taken by imaging unit.
2. Description of the Related Art
With the rapid development and spread of digital still cameras, images are readily available in the form of digital data. There is a proposed technique of automatically adjusting the contrast in displayed or printed images (see, for example, Patent Document 1: Japanese Patent Laid-Open Gazette No. 10-198802).
Another proposed technique is applied to an imaging device having three CCDs (charge coupled devices) provided corresponding to three primary colors to detect a defect of each CCD (see, for example, Patent Document 2: Japanese Patent Laid-Open Gazette No. 5-268531).
A recently advanced digital still camera has CCDs corresponding to respective pixels and allocates one of three primary color filters of red, green, and blue to each CCD. The CCD at each pixel outputs one color signal corresponding to the allocated color filter. The technique disclosed in Patent Document 2, on the other hand, detects a defect of each of the three CCDs provided corresponding to the three primary colors. Because of the essential structural difference from the digital still camera having CCDs corresponding to the respective pixels, the defect detection technique for detecting a pixel defect of this digital still camera is different from the defect detection technique for defecting the detect of each of the three CCDs provided corresponding to the three primary colors.